Joint mechanism



Oct. 14, 1930. c, LQRD 1,778,197

JOINT MECHANI SM Filed Jan. 21, 1927 INVEfQR.

Patented Oct. 14, 1930 HUGH G. L031), ERIE, PENNSYLVANIA JOINT MECHAN 18H -Lpp11cation flled lanuary 8 1, 1997. Serial No. 182,808. Y

The present invention is directed to joint mechanisms in which there is a wobble movement of one member relatively to the-other which, in the preferred joint mechanism, in-

volves an oscillatory movement on more than one axis. It is particularly useful with joints having a comparatively large movement about one axis and a comparatively small movement about another axis, as for example the joints at the outer ends of the drag link in tie rods of an automobile.

A preferred embodiment of the invention is illustrated in the accompanying drawings as follows 1 Fig. 1 shows a plan view of the front axle of an automobile with a steering gear thereon.

2 an enlarged sectional view'of one of the joints on the line 22 in Fig. 3.

1 marks an automobile axle, 2 the front wheels, and 3 the king bolts, the front wheels being slightly off perpendicular. Knuckles 4 are journaled on the king bolts and carry the wheels and are provided with the usual arms 4 A tie rod-6 extends between the arms and terminates in clevises 7 Each joint is provided with the clevis 7 and a bolt 8 extending between the arms of the clevis, said bolt having a head 8'? and a clamping nut 8". The bolt extends through an inner joint member 9 in the form of a metallic sleeve. A rubber joint member 10 is arranged on the sleeve 9 and within a shell 11. The shell is pressed into sockets 5 in the knuckle arms.

Preferably the rubber is secured to the surfaces of the inner and outer-joint members by uniting the engaging surfaces and this can be particularly well accomplished during vulcanization. A drag link arm 12 is secured to one of the knuckles and a drag link 13 extends from this arm to a rock arm 14 of the steering gear, the rock arm being fixed on.a shaft 15 and swings on the axis of the shaft 15 in the usual manner. At the ends of the drag links there are joints exactly similar to those at the ends of the tie rods, namely having the clevises 7-7, the connecting bolts 50 8-8, and the rubber-joint element pressed Fig. 3 a section on the line 33 in Fig. 2.

into an eye 12" on the draglink arm 12 and 14 on the steering gear arm. At the ends of the drag link it Wlll be noted that there is oscillator movement on the axis of the sleeve 9 of considerable amplitude and in addition thereto there is. a swingin movement with an axis across the axis 0 the inner joint member. At the front end of the drag link this cross swinging is due to the raising and lowering of the frame-due to the swin ing action and also to the arc of travel 0 the end of the arm 14. Similarly the joint at the lower end of the arm 14 has an oscillatory movement due to the swinging of the arm on the axis of the sleeve 9 and also a cross move ment due to the arc of travel of the end of the arm 12.

, The shell 11 is short compared to the diameter of the joint. Consequently if the joint is swung across the axis the movement at the ends of the outer shell is more nearly in line with the axis of the joint member than a radial direction. Itwill be understood that this cocking of the shell 11 due to this swingon this cross axis tends to compress the 1n rubber at opposite ends and diagonally across the rubber. If the rubber is comparatively short the radial movement at the ends of the shell is less pronounced than with a shell that is longer as comparedto its diameter. It is this stressing of the rubber that limits the cross swinging of the joint. I prefer, therefore, to have the meeting points a of the ends of the rubber with the shell positioned'at less than an angle of 45 from a plane indicated at b?) in Fig. 2 and perpendicular to the longitudinal axis 00 with the vertex of the angle at the radial and axial center (1 of the joint. It will be seen that the 45 line de is some distance from the meeting points a between the rubber and the shell and the arc af is more nearly axial than radial so that the rubber at theends is moved somewhat in an endwise direction as the joint is flexed crosswise; whereas, if the meeting points between the ends of the rubber and the shell were at the 45 line so as to move in an are as gh the movement at the ends would be more nearly radial than axial with a consequent direct compression, and the crosswise flexing would, therefore, be reduced. I prefer to make the inner member of the joint slightl longer than the outer member so that t e mass of rubber immediately surrounding the inner member will more nearly approximate the mass of rubber immediately ad acent to the outer shell and I also prefer to have therubber at the ends'extend inwardl from the path of movement of-the end 0 the shell under the crosswise swinging of the joint. As shown the end of the rubber is cupped and this reduces the banking up of the rubber under the end of the shell as it is swung crosswise. Further I prefer to place the rubber in the joint under initial tension and this maybe accomplished by bonding the rubber to the shell and pin during vulcanization. Upon the cooling of the rubber it shrinks suificientl to put the rubber of the joint under initia tension. Consequently as the shell is cocked, or swung crosswise this initial tension at the point Where the shell moves toward the inner pin 9 moves some distance in neutralizing the initial tension before compressing the rubber at this point and thus subjecting it to the stresses incident to this crosswise movement. With the rubber united with the engaging surfaces of the pin and shell it will be understood that if the pin is of the same length as the shell the bond at the pin, particularly at the tension side, is subject to a much greater breaking strain than the bond at the shell, because a much less area of bond must sustain the same load. By making the bonding surface at the pin longer the difi'erence between the pin and shell as to bond' area may be eliminated or reduced. This is of greater advantage with the rubber under initial tension, as the tension side of the joint then carries a greater proportion of the oad.

With such a structure it is possible with joint mechanisms, such as tie rods, to accomplish the compound movement of the joints with a single joint, thus avoiding a multiplication of joints, or the formin of an ordinary knuckle joint at each end oi the rod.

What I claim as new is 1. In a joint, the combination of an outer annular member, an inner member within the outer member, and a rubber member between the outer and inner members, said rubber member being longer at the inner member than at the outer member, the meeting points of the ends of the rubber member with the outer member being positioned at less than an angle of 45 from a plane perpendicular to the longitudinal axis With the vertex of said angle at the radial and axial center of the joint.

2. In a joint member, the combination of an annular outer member; an inner member within the outer member; and a rubber member between the outer and inner'merrnbers, the rubber member being longer at the inner member than at the meeting points of its ends with the outer member and said rubber member having its ends cupped.

3. In a joint member, the combination of an annular outer member; an inner member within the outer member; and a rubber member between and engaging the inner and outer surfacesof the outer and inner members re spectively, the rubber member being longer at the inner member than at the outer member, said rubber being united to the outer and inner members by a radial tension-res1st1ng umon between the engaging surfaces uniting the rubber member with the outer my hand.

HUGH C. LORD. 

